The present invention relates to an all purpose hard surface cleaning or microemulsion composition having improved foam profile properties.
This invention relates to an improved all-purpose liquid cleaner which can be in the form of a microemulsion designed in particular for cleaning hard surfaces and which is effective in removing grease soil and/or bath soil and in leaving unrinsed surfaces with a shiny appearance as well as having improved profile foam properties.
In recent years all-purpose liquid detergents have become widely accepted for cleaning hard surfaces, e.g., painted woodwork and panels, tiled walls, wash bowls, bathtubs, linoleum or tile floors, washable wall paper, etc. Such all-purpose liquids comprise clear and opaque aqueous mixtures of water-soluble synthetic organic detergents and water-soluble detergent builder salts. In order to achieve comparable cleaning efficiency with granular or powdered all-purpose cleaning compositions, use of water-soluble inorganic phosphate builder salts was favored in the prior art all-purpose liquids. For example, such early phosphate-containing compositions are described in U.S. Pat. Nos. 2,560,839; 3,234,138; 3,350,319; and British Patent No. 1,223,739.
In view of the environmentalist""s efforts to reduce phosphate levels in ground water, improved all-purpose liquids containing reduced concentrations of inorganic phosphate builder salts or non-phosphate builder salts have appeared. A particularly useful self-opacified liquid of the latter type is described in U.S. Pat. No. 4,244,840.
However, these prior art all-purpose liquid detergents containing detergent builder salts or other equivalent tend to leave films, spots or streaks on cleaned unrinsed surfaces, particularly shiny surfaces. Thus, such liquids require thorough rinsing of the cleaned surfaces which is a time-consuming chore for the user.
In order to overcome the foregoing disadvantage of the prior art all-purpose liquid, U.S. Pat. No. 4,017,409 teaches that a mixture of paraffin sulfonate and a reduced concentration of inorganic phosphate builder salt should be employed. However, such compositions are not completely acceptable from an environmental point of view based upon the phosphate content. On the other hand, another alternative to achieving phosphate-free all-purpose liquids has been to use a major proportion of a mixture of anionic and nonionic detergents with minor amounts of glycol ether solvent and organic amine as shown in U.S. Pat. No. 3,935,130. Again, this approach has not been completely satisfactory and the high levels of organic detergents necessary to achieve cleaning cause foaming which, in turn, leads to the need for thorough rinsing which has been found to be undesirable to today""s consumers.
Another approach to formulating hard surfaced or all-purpose liquid detergent composition where product homogeneity and clarity are important considerations involves the formation of oil-in-water (o/w) microemulsions which contain one or more surface-active detergent compounds, a water-immiscible solvent (typically a hydrocarbon solvent), water and a xe2x80x9ccosurfactantxe2x80x9d compound which provides product stability. By definition, an o/w microemulsion is a spontaneously forming colloidal dispersion of xe2x80x9coilxe2x80x9d phase particles having a particle size in the range of 25 to 800 xc3x85 in a continuous aqueous phase.
In view of the extremely fine particle size of the dispersed oil phase particles, microemulsions are transparent to light and are clear and usually highly stable against phase separation.
Patent disclosures relating to use of grease-removal solvents in o/w microemulsions include, for example, European Patent Applications EP 0137615 and EP 0137616xe2x80x94Herbots et al; European Patent Application EP 0160762xe2x80x94Johnston et al; and U.S. Pat. No. 4,561,991xe2x80x94Herbots et al. Each of these patent disclosures also teaches using at least 5% by weight of grease-removal solvent.
It also is known from British Patent Application GB 2144763A to Herbots et al, published Mar. 13, 1985, that magnesium salts enhance grease-removal performance of organic grease-removal solvents, such as the terpenes, in o/w microemulsion liquid detergent compositions. The compositions of this invention described by Herbots et al. require at least 5% of the mixture of grease-removal solvent and magnesium salt and preferably at least 5% of solvent (which may be a mixture of water-immiscible non-polar solvent with a sparingly soluble slightly polar solvent) and at least 0.1% magnesium salt.
However, since the amount of water immiscible and sparingly soluble components which can be present in an o/w microemulsion, with low total active ingredients without impairing the stability of the microemulsion is rather limited (for example, up to 18% by weight of the aqueous phase), the presence of such high quantities of grease-removal solvent tend to reduce the total amount of greasy or oily soils which can be taken up by and into the microemulsion without causing phase separation.
The following representative prior art patents also relate to liquid detergent cleaning compositions in the form of o/w microemulsions: U.S. Pat. Nos. 4,472,291xe2x80x94Rosario; 4,540,448xe2x80x94Gauteer et al; 3,723,330xe2x80x94Sheflin; etc.
Liquid detergent compositions which include terpenes, such as d-limonene, or other grease-removal solvent, although not disclosed to be in the form of o/w microemulsions, are the subject matter of the following representative patent documents: European Patent Application 0080749; British Patent Specification 1,603,047; and U.S. Pat. Nos. 4,414,128; and 4,540,505. For example, U.S. Pat. No. 4,414,128 broadly discloses an aqueous liquid detergent composition characterized by, by weight:
(a) from 1% to 20% of a synthetic anionic, nonionic, amphoteric or zwitterionic surfactant or mixture thereof;
(b) from 0.5% to 10% of a mono- or sesquiterpene or mixture thereof, at a weight ratio of (a):(b) being in the range of 5:1 to 1:3; and
(c) from 0.5% 10% of a polar solvent having a solubility in water at 15xc2x0 C. in the range of from 0.2% to 10%. Other ingredients present in the formulations disclosed in this patent include from 0.05% to 2% by weight of an alkali metal, ammonium or alkanolammonium soap of a C13-C24 fatty acid; a calcium sequestrant from 0.5% to 13% by weight; non-aqueous solvent, e.g., alcohols and glycol ethers, up to 10% by weight; and hydrotropes, e.g., urea, ethanolamines, salts of lower alkylaryl sulfonates, up to 10% by weight. All of the formulations shown in the Examples of this patent include relatively large amounts of detergent builder salts which are detrimental to surface shine.
A pH neutral microemulsion composition based on paraffin sulfonate and ethoxylated nonionic surfactant is able to deliver improved grease cleaning versus built, alkaline compositions. Besides the improved grease cleaning, this approach is much safer to surfaces as well as less aggressive on consumer""s hands (Loth et alxe2x80x94U.S. Pat. No. 5,075,026).
The microemulsion technology provides outstanding oil uptake capacity because of the adjustment of the curvature of the surfactant micelles by the molecules of the cosurfactant. Rod-like micelles are preferred as they can xe2x80x9cswallowxe2x80x9d oil to become globular without increasing the surface of contact between the hydrophobic core of the micelle and the hydrophilic continuous phase.
In diluted usage however, the microemulsion state is usually lost and the cleaning performance relies on the adsorption efficacy and leaving character of the surfactant system. Nonionic surfactants perform very well on grease, as they are excellent grease xe2x80x9csolubilizersxe2x80x9d. Actually, they spontaneously form swollen micelles. In moderate climate countries such as the northern states of the United States and the northern countries of Europe, the soil on the hard surfaces contains a major proportion of greasy materials. It is accordingly not surprising that the anionic-nonionic surfactant based microemulsion is so efficient in those countries. In hot weather countries however, the amount of particulate soils is more important (as doors and windows remain open) and the classical microemulsion (U.S. Pat. No. 5,075,026) shows weaknesses on this type of soil which is a mixed grease-particulate soil in nature.
The instant invention teaches that the foam profile properties of an all purpose anionic cleaning or microemulsion compositions can be improved by the addition of select foam control agents.
The present invention provides an improved, clear, liquid cleaning composition having improved foam profile properties and interfacial tension which improves cleaning hard surfaces such as plastic, vitreous and metal surfaces having a shiny finish, oil stained floors, automotive engines and other engines as well as having improved foam collapse properties. More particularly, the improved cleaning compositions exhibit good grease soil removal properties due to the improved interfacial tensions, and leave the cleaned surfaces shiny without the need of or requiring only minimal additional rinsing or wiping. The latter characteristic is evidenced by little or no visible residues on the unrinsed cleaned surfaces and, accordingly, overcomes one of the disadvantages of prior art products.
Surprisingly, these desirable results are accomplished even in the absence of polyphosphate or other inorganic or organic detergent builder salts and also in the complete absence or substantially complete absence of grease-removal solvent.
In one aspect, the invention generally provides a stable, clear all-purpose, hard surface cleaning composition having improved foam profile properties which is especially effective in the removal of oily and greasy oil. The cleaning composition includes, on a weight basis:
about 0.25 to about 40 wt. %, more preferably about 0.5 to about 20 wt. % of an anionic surfactant;
0.25% to about 4%, more preferably 0.5% to 3% of a foam control agent;
0 to about 15% of magnesium sulfate heptahydrate;
about 0 to about 10.0% of a perfume, essential oil or water insoluble hydrocarbon; and
the balance being water, said proportions being based upon the total weight of the composition.
The cleaning composition can be in the form of a microemulsion in which case the concentration of the water mixable cosurfactant is about 0 to 50.0 wt. %, preferably 1 wt. % to about 20 wt. % and the concentration of the perfume, essential oil or water insoluble hydrocarbon is about 0.4 wt. % to about 10.0 wt. %.
The present invention relates to a stable all purpose cleaning or microemulsion composition comprising approximately by weight: 0.25% to 40% of an anionic surfactant, 0 to 50% of a cosurfactant, 0.25% to 4% of a foam control agent, 0 to 10% of a water insoluble hydrocarbon or a perfume and the balance being water. The instant compositions excluded the use of polyhydroxy fatty acid amides, ethoxylated or ethoxylated/propoxylated nonionic surfactants, formed from the condensation product of primary alcohols and ethylene oxide or ethylene oxide and propylene oxide, zwitterionic surfactants because the use of these surfactants reduce the effectiveness of the foam control agent. The instant compositions exclude the use of grease release agents such as 
wherein X is hydrogen or an alkali metal cation and n is a number from 2 to 16, R1 is selected from the group consisting of methyl or hydrogen, R2 is a C1 to C12 linear or branched chained alkyl group and R3 is a C2 to C16 linear or branched chained alkyl group and y is of such value as to provide a molecular weight about 5,000 to about 15,000 or a polyethylene glycol. The cleaning composition can be in the form of a microemulsion in which case the concentration of the water mixable cosurfactant is about 0 to about 50.0 wt. %, preferably about 0.1 wt. % to about 25.0 wt. % and the concentration of the perfume, essential oil or water insoluble hydrocarbon is about 0.4 wt. % to about 10.0 wt. %.
Excluded from the instant compositions are benzyl alchol, polyethoxylated phenols containing from 2 to 6 ethoxy groups, phenyl ethyl alcohol, mono C6-C9 alkyl ethers of ethylene glycol, di C4-C9 alkyl ethers of ethylene glycol and esters and esters of C1-C6 fatty acids with C1-C6 alcohols containing a total of from 5 to 9 carbon atoms.
According to the present invention, the role of the hydrocarbon can be provided by a non-water-soluble perfume. Typically, in aqueous based compositions the presence of a solubilizers, such as alkali metal lower alkyl aryl sulfonate hydrotrope, triethanolamine, urea, etc., is required for perfume dissolution, especially at perfume levels of 1% and higher, since perfumes are generally a mixture of fragrant essential oils and aromatic compounds which are generally not water-soluble. Therefore, by incorporating the perfume into the aqueous cleaning composition as the oil (hydrocarbon) phase of the microemulsion composition, several different important advantages are achieved.
First, the cosmetic properties of the ultimate cleaning composition are improved: the compositions are both clear (as a consequence of the formation of a microemulsion) and highly fragranced (as a consequence of the perfume level).
Second, the need for use of solubilizers, which do not contribute to cleaning performance, is eliminated.
Third, an improved grease release effect and an improved grease removal capacity in neat (undiluted) usage of the dilute aspect or after dilution of the concentrate can be obtained without detergent builders or buffers or conventional grease removal solvents at neutral or acidic pH and at low levels of active ingredients while improved cleaning performance can also be achieved in diluted usage.
As used herein and in the appended claims the term xe2x80x9cperfumexe2x80x9d is used in its ordinary sense to refer to and include any non-water soluble fragrant substance or mixture of substances including natural (i.e., obtained by extraction of flower, herb, blossom or plant), artificial (i.e., mixture of natural oils or oil constituents) and synthetically produced substance) odoriferous substances. Typically, perfumes are complex mixtures of blends of various organic compounds such as alcohols, aldehydes, ethers, aromatic compounds and varying amounts of essential oils (e.g., terpenes) such as from 0% to 80%, usually from 10% to 70% by weight. The essential oils themselves are volatile odoriferous compounds and also serve to dissolve the other components of the perfume.
In the present invention the precise composition of the perfume is of no particular consequence to cleaning performance so long as it meets the criteria of water immiscibility and having a pleasing odor. Naturally, of course, especially for cleaning compositions intended for use in the home, the perfume, as well as all other ingredients, should be cosmetically acceptable, i.e., non-toxic, hypoallergenic, etc.
The hydrocarbon such as a perfume is present in the hard surface cleaning composition in an amount of from 0 to 10% by weight, preferably 0.4% to 10% by weight and most preferably from 0.4% to 3.0% by weight, especially preferably from 0.5% to 2.0% by weight. If the hydrocarbon (perfume) is added in amounts more than 10% by weight, the cost is increased without any additional cleaning benefit and, in fact, with some diminishing of cleaning performance insofar as the total amount of greasy or oily soil which can be taken up in the oil phase of the microemulsion will decrease proportionately.
Furthermore, although superior grease removal performance will be achieved for perfume compositions not containing any terpene solvents, it is apparently difficult for perfumers to formulate sufficiently inexpensive perfume compositions for products of this type (i.e., very cost sensitive consumer-type products) which includes less than 20%, usually less than 30%, of such terpene solvents.
Thus, merely as a practical matter, based on economic consideration, the microemulsion compositions of the present invention may often include as much as 0.2% to 7% by weight, based on the total composition, of terpene solvents introduced thereunto via the perfume component. However, even when the amount of terpene solvent in the cleaning formulation is less than 1.5% by weight, such as up to 0.6% by weight or 0.4% by weight or less, satisfactory grease removal and oil removal capacity is provided by the inventive diluted microemulsions.
Thus, for a typical formulation of a diluted microemulsion according to this invention a 20 milliliter sample of microemulsion containing 1% by weight of perfume will be able to solubilize, for example, up to 2 to 3 ml of greasy and/or oily soil, while retaining its form as a microemulsion, regardless of whether the perfume contains 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% or 0.8% by weight of terpene solvent.
In place of the perfume one can employ a water insoluble essential oil, or water insoluble saturated or unsaturated organic compound or isoparaffin having 6 to 18 carbon at a concentration of 0 to 8.0 wt. %, preferably 0.4 to 8.0 wt. percent, more preferably 0.4 to 3.0 wt. %.
The water insoluble saturated or unsaturated organic compounds contain 4 to 20 carbon atoms and up to 4 different or identical functional groups and is used at a concentration of about 1.0 wt. % to about 8 wt. %, more preferably about 2.0 wt. % to about 7 wt. %. Examples of acceptable water insoluble saturated or unsaturated organic compound include (but are not limited to) water insoluble hydrocarbons containing 0 to 4 different or identical functional groups, water insoluble aromatic hydrocarbons containing 0 to 4 different or identical functional groups, water insoluble heterocyclic compounds containing 0 to 4 different or identical functional groups, water insoluble ethers containing 0 to 3 different or identical functional groups, water insoluble alcohols containing 0 to 3 different or identical functional groups, water insoluble amines containing 0 to 3 different or identical functional groups, water insoluble esters containing 0 to 3 different or identical functional groups, water insoluble carboxylic acids containing 0 to 3 different or identical functional groups, water insoluble amides containing 0 to 3 different or identical functional groups, water insoluble nitriles containing 0 to 3 different or identical functional group, water insoluble aldehydes containing 0 to 3 different or identical functional groups, water insoluble ketones containing 0 to 3 different or identical functional groups, water insoluble phenols containing 0 to 3 different or identical functional groups, water insoluble nitro compounds containing 0 to 3 different or identical functional groups, water insoluble halogens containing 0 to 3 different or identical functional groups, water insoluble sulfates or sulfonates containing 0 to 3 different or identical functional groups, limonene, dipentene, terpineol, essential oils, perfumes, water insoluble organic compounds containing up to 4 different or identical functional groups such as an alkyl cyclohexane having both three hydroxys and one ester group and mixture thereof.
Typical heterocyclic compounds are 2,5-dimethylhydrofuran, 2-methyl-1,3-dioxolane, 2-ethyl 2-methyl 1,3 dioxolane, 3-ethyl 4-propyl tetrahydropyran, 3-morpholino-1,2-propanediol and N-isopropyl morpholine A typical amine is alpha-methyl benzyldimethylamine. Typical halogens are 4-bromotoluene, butyl chloroform and methyl perchloropropane. Typical hydrocarbons are 1,3-dimethylcyclohexane, cyclohexyl-1 decane, methyl-3 cyclohexyl-9 nonane, methyl-3 cyclohexyl-6 nonane, dimethyl cycloheptane, trimethyl cyclopentane, ethyl-2 isopropyl-4 cyclohexane. Typical aromatic hydrocarbons are bromotoluene, diethyl benzene, cyclohexyl bromoxylene, ethyl-3 pentyl-4 toluene, tetrahydronaphthalene, nitrobenzene and methyl naphthalene. Typical water insoluble esters are benzyl acetate, dicyclopentadienylacetate, isononyl acetate, isobornyl acetate and isobutyl isobutyrate. Typical water insoluble ethers are di(alphamethyl benzyl) ether and diphenyl ether. Typical alcohols are phenoxyethanol and 3-morpholino-1,2-propanediol. Typical water insoluble nitro derivatives are nitro butane and nitrobenzene.
Suitable essential oils are selected from the group consisting of: Anethole 20/21 natural, Aniseed oil china star, Aniseed oil globe brand, Balsam (Peru), Basil oil (India), Black pepper oil, Black pepper oleoresin 40/20, Bois de Rose (Brazil) FOB, Borneol Flakes (China), Camphor oil, White, Camphor powder synthetic technical, Cananga oil (Java), Cardamom oil, Cassia oil (China), Cedarwood oil (China) BP, Cinnamon bark oil, Cinnamon leaf oil, Citronella oil, Clove bud oil, Clove leaf, Coriander (Russia), Coumarin 69xc2x0 C. (China), Cyclamen Aldehyde, Diphenyl oxide, Ethyl vanilin, Eucalyptol, Eucalyptus oil, Eucalyptus citriodora, Fennel oil, Geranium oil, Ginger oil, Ginger oleoresin (India), White grapefruit oil, Guaiacwood oil, Gurjun balsam, Heliotropin, Isobornyl acetate, Isolongifolene, Juniper berry oil, L-methyl acetate, Lavender oil, Lemon oil, Lemongrass oil, Lime oil distilled, Litsea Cubeba oil, Longifolene, Menthol crystals, Methyl cedryl ketone, Methyl chavicol, Methyl salicylate, Musk ambrette, Musk ketone, Musk xylol, Nutmeg oil, Orange oil, Patchouli oil, Peppermint oil, Phenyl ethyl alcohol, Pimento berry oil, Pimento leaf oil, Rosalin, Sandalwood oil, Sandenol, Sage oil, Clary sage, Sassafras oil, Spearmint oil, Spike lavender, Tagetes, Tea tree oil, Vanilin, Vetyver oil (Java), Wintergreen, Allocimene, Arbanex(trademark), Arbanol(copyright), Bergamot oils, Camphene, Alpha-Campholenic aldehyde, I-Carvone, Cineoles, Citral, Citronellol Terpenes, Alpha-Citronellol, Citronellyl Acetate, Citronellyl Nitrile, Para-Cymene, Dihydroanethole, Dihydrocarveol, d-Dihydrocarvone, Dihydrolinalool, Dihydromyrcene, Dihydromyrcenol, Dihydromyrcenyl Acetate, Dihydroterpineol, Dimethyloctanal, Dimethyloctanol, Dimethyloctanyl Acetate, Estragole, Ethyl-2 Methylbutyrate, Fenchol, Fernlol(trademark), Florilys(trademark), Geraniol, Geranyl Acetate, Geranyl Nitrile, Glidmint(trademark) Mint oils, Glidox(trademark), Grapefruit oils, trans-2-Hexenal, trans-2-Hexenol, cis-3-Hexenyl Isovalerate, cis-3-Hexanyl-2-methylbutyrate, Hexyl Isovalerate, Hexyl-2-methylbutyrate, Hydroxycitronellal, Ionone, Isobornyl Methylether, Linalool, Linalool Oxide, Linalyl Acetate, Menthane Hydroperoxide, I-Methyl Acetate, Methyl Hexyl Ether, Methyl-2-methylbutyrate, 2-Methylbutyl Isovalerate, Myrcene, Nerol, Neryl Acetate, 3-Octanol, 3-Octyl Acetate, Phenyl Ethyl-2-methylbutyrate, Petitgrain oil, cis-Pinane, Pinane Hydroperoxide, Pinanol, Pine Ester, Pine Needle oils, Pine oil, alpha-Pinene, beta-Pinene, alpha-Pinene Oxide, Plinol, Plinyl Acetate, Pseudo Ionone, Rhodinol, Rhodinyl Acetate, Spice oils, alpha-Terpinene, gamma-Terpinene, Terpinene-4-OL, Terpineol, Terpinolene, Terpinyl Acetate, Tetrahydrolinalool, Tetrahydrolinalyl Acetate, Tetrahydromyrcenol, Tetralol(copyright), Tomato oils, Vitalizair, Zestoral(trademark).
The anionic surfactants which may be used in the instant compositions of this invention are water soluble such as triethanolamine and include the sodium, potassium, ammonium and ethanolammonium salts of C8-C18 alkyl sulfates such as lauryl sulfate, myristyl sulfate and the like; linear C8-C16 alkyl benzene sulfonates; C10-C20 paraffin sulfonates and alpha olefin sulfonates containing about 10-24 carbon atoms and mixtures thereof. Preferred anionic surfactants are the water soluble C12-C16 alkyl sulfates, the C10-C15 alkylbenzene sulfonates, the C13-C17 paraffin sulfonates and the alpha C12-C18 olefin sulfonates.
The foam control agent employed in the instant invention are used as a means of either reducing initial foaming or destabilizing the resultant foam so that a maximum decrease in foaming can be achieved within a specified time. The foaming agents are selected from the group consisting of organic monoesters formed from a C6 to C20 aliphatic fatty acid and a C6 to C20 aliphatic alcohol, wherein the organic monoester has at least 12 carbon atoms and mere preferably at least 14 carbon atoms, and C8-C12 organic diols. Specific foam control agents are isohexyl neopentanoate, isopropyl myristate, myreth-3-myristate, laureth-2(ethyl2hexanoate), 1,8-octane diol, and 1,10-decane diol.
A cosurfactant can be optionally used in forming the microemulsion composition. Three major classes of compounds have been found to provide highly suitable cosurfactants over temperature ranges extending from 4xc2x0 C. to 43xc2x0 C. for instance; (1) water-soluble C3-C4 alkanols, polypropylene glycol of the formula HO(CH3CHCH2O)nH wherein n is a number from 2 to 18 and copolymers of ethylene oxide and propylene oxide and mono C1-C6 alkyl ethers and esters of ethylene glycol and propylene glycol having the structural formulas R(X)nOH and R1(X)nOH wherein R is C1-C4 alkyl, R1 is C2-C4 acyl group, X is (OCH2CH2) or (OCH2 (CH3)CH) and n is a number from 1 to 4; (2) aliphatic mono- and di-carboxylic acids containing 2 to 10 carbon atoms, preferably 3 to 6 carbons in the molecule; and (3) triethyl phosphate. Additionally, mixtures of two or more of the three classes of cosurfactant compounds may be employed where specific pH""s are desired.
When the mono- and di-carboxylic acid (Class 2) cosurfactants are employed in the instant microemulsion compositions at a concentration of 2 to 10 wt. %, the microemulsion compositions can be used as a cleaners for bathtubs and other hard surfaced items, which are acid resistant thereby removing lime scale, soap scum and greasy soil from the surfaces of such items damaging such surfaces. If these surfaces are of zirconium white enamel, they can be damaged by these compositions.
An aminoalkylene phophoric acid at a concentration of 0.01 to 0.2 wt. % can be optionally used in conjunction with the mono- and di-carboxylic acids, wherein the aminoalkylene phosphoric acid helps prevent damage to zirconium white enamel surfaces. Additionally, 0.05 to 1% of phosphoric acid can be used in the composition.
Representative members of the polypropylene glycol include dipropylene glycol and polypropylene glycol having a molecular weight of 200 to 1000, e.g., polypropylene glycol 400. Representative glycol ethers are ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether (butyl carbitol), dipropylene glycol monomethyl ether, triethylene glycol monobutyl ether, mono, di, tri propylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, propylene glycol tertiary butyl ether, ethylene glycol monoacetate and dipropylene glycol propionate.
Representative members of the aliphatic carboxylic acids include C3-C6 alkyl and alkenyl monobasic acids such as acrylic acid and propionic acid and dibasic acids such as glutaric acid and mixtures of glutaric acid with adipic acid and succinic acid, as well as mixtures of the foregoing acids.
While all of the aforementioned glycol ether compounds and acid compounds provide the described stability, the most preferred cosurfactant compounds of each type, on the basis of cost and cosmetic appearance (particularly odor), are diethylene glycol monobutyl ether and a mixture of adipic, glutaric and succinic acids, respectively. The ratio of acids in the foregoing mixture is not particularly critical and can be modified to provide the desired odor. Generally, to maximize water solubility of the acid mixture glutaric acid, the most water-soluble of these three saturated aliphatic dibasic acids, will be used as the major component.
Generally, weight ratios of adipic acid: glutaric acid:succinic acid is 1-3:1-8:1-5, preferably 1-2:1-6:1-3, such as 1:1:1, 1:2:1, 2:2:1, 1:2:1.5, 1:2:2, 2:3:2, etc. can be used with equally good results.
Still other classes of cosurfactant compounds providing stable microemulsion compositions at low and elevated temperatures are the mono-, di- and triethyl esters of phosphoric acid such as triethyl phosphate.
The amount of cosurfactant which might be required to stabilize the microemulsion compositions will, of course, depend on such factors as the surface tension characteristics of the cosurfactant, the type and amounts of the analephotropic complex and perfumes, and the type and amounts of any other additional ingredients which may be present in the composition and which have an influence on the thermodynamic factors enumerated above. Generally, amounts of cosurfactant in the range of from 0 to 50 wt. %, preferably from 0.1 wt. % to 25 wt. %, especially preferably from 0.5 wt. % to 15 wt. %, by weight provide stable microemulsions for the above-described levels of primary surfactants and perfume and any other additional ingredients as described below.
As will be appreciated by the practitioner, the pH of the final microemulsion will be dependent upon the identity of the cosurfactant compound, with the choice of the cosurfactant being effected by cost and cosmetic properties, particularly odor. For example, microemulsion compositions which have a pH in the range of 1 to 10 may employ either the class 1 or the class 4 cosurfactant as the sole cosurfactant, but the pH range is reduced to 1 to 8.5 when the polyvalent metal salt is present. On the other hand, the class 2 cosurfactant can only be used as the sole cosurfactant where the product pH is below 3.2. However, where the acidic cosurfactants are employed in admixture with a glycol ether cosurfactant, compositions can be formulated at a substantially neutral pH (e.g., pH 7xc2x11.5, preferably 7xc2x10.2).
The ability to formulate neutral and acidic products without builders which have grease removal capacities is a feature of the present invention because the prior art microemulsion formulations most usually are highly alkaline or highly built or both.
The final essential ingredient in the hard surface cleaning compositions having improved interfacial tension properties is water. The proportion of water in the hard surface cleaning compositions generally is in the range of 20 wt. % to 97 wt. %, preferably 70 wt. % to 97 wt. % of the usual diluted o/w microemulsion composition.
In addition to the above-described essential ingredients required for the formation of the all purpose hard surface cleaning compositions, the compositions of this invention may often and preferably do contain one or more additional ingredients which serve to improve overall product performance.
One such ingredient is an inorganic or organic salt of oxide of a multivalent metal cation, particularly Mg++. The metal salt or oxide provides several benefits including improved cleaning performance in dilute usage, particularly in soft water areas, and minimized amounts of perfume required to obtain the microemulsion state. Magnesium sulfate, either anhydrous or hydrated (e.g., heptahydrate), is especially preferred as the magnesium salt. Good results also have been obtained with magnesium oxide, magnesium chloride, magnesium acetate, magnesium propionate and magnesium hydroxide. These magnesium salts can be used with formulations at neutral or acidic pH since magnesium hydroxide will not precipitate at these pH levels.
Although magnesium is the preferred multivalent metal from which the salts (inclusive of the oxide and hydroxide) are formed, other polyvalent metal ions also can be used provided that their salts are nontoxic and are soluble in the aqueous phase of the system at the desired pH level.
Thus, depending on such factors as the pH of the system, the nature of the complex and cosurfactant, as well as the availability and cost factors, other suitable polyvalent metal ions include aluminum, copper, nickel, iron, calcium, etc. It should be noted, for example, that with the preferred paraffin sulfonate anionic detergent calcium salts will precipitate and should not be used. It has also been found that the aluminum salts work best at pH below 5 or when a low level, for example 1 weight percent, of citric acid is added to the composition which is designed to have a neutral pH. Alternatively, the aluminum salt can be directly added as the citrate in such case. As the salt, the same general classes of anions as mentioned for the magnesium salts can be used, such as halide (e.g., bromide, chloride), sulfate, nitrate, hydroxide, oxide, acetate, propionate, etc.
The proportion of the multivalent salt generally will be selected so that at the appropriate weight ratio between the anionic surfactant and the zwitterionic surfactant, amine oxide or alkylene carbonate to deliver desired performance from the complex in terms of adsorption properties on grease surface, the physical stability of the total composition is kept, that can be impaired due to an increased hydrophobicity of the analephotropic complex in the presence of multivalent salt instead of alkali metal cation such as the sodium salt thereof. As a consequence, the proportion of the multivalent salt will be selected so that the added quantity will neutralize from 0.1 to 1.5 equivalents of the anionic surfactant, preferably 0.9 to 1.4 equivalents of the acid form of the anionic surfactant. At higher concentrations of anionic surfactant, the amount of multivalent salt will be in range of 0.5 to 1 equivalents per equivalent of anionic surfactant.
The all-purpose liquid cleaning or microemulsion composition of this invention may, if desired, also contain other components either to provide additional effect or to make the product more attractive to the consumer. The following are mentioned by way of example: Colors or dyes in amounts up to 0.5% by weight; bactericides in amounts up to 1% by weight; preservatives or antioxidizing agents, such as formalin, 5-chloro-2-methyl-4-isothaliazolin-3-one, 2,6-di-tert.butyl-p-cresol, etc., in amounts up to 2% by weight; and pH adjusting agents, such as sulfuric acid or sodium hydroxide, as needed. Furthermore, if opaque compositions are desired, up to 4% by weight of an opacifier may be added.
In final form, the all-purpose cleaning or clear microemulsions exhibit stability at reduced and increased temperatures. More specifically, such compositions remain clear and stable in the range of 4xc2x0 C. to 50xc2x0 C., especially 10xc2x0 C. to 43xc2x0 C. Such compositions exhibit a pH in the acid or neutral range depending on intended end use. The liquids are readily pourable and exhibit a viscosity in the range of 6 to 60 milliPascalxe2x80x94Second (mPas.) as measured at 25xc2x0 C. with a Brookfield RVT Viscometer using a #1 spindle rotating at 20 RPM. Preferably, the viscosity is maintained in the range of 10 to 40 mPas.
The compositions are directly ready for use or can be diluted as desired and in either case no or only minimal rinsing is required and substantially no residue or streaks are left behind. Furthermore, because the compositions are free of detergent builders such as alkali metal polyphosphates they are environmentally acceptable and provide a better xe2x80x9cshinexe2x80x9d on cleaned hard surfaces.
When intended for use in the neat form, the liquid compositions can be packaged under pressure in an aerosol container or in a pump-type sprayer for the so-called spray-and-wipe type of application.
Because the compositions as prepared are aqueous liquid formulations and since no particular mixing is required to form the all purpose cleaning or microemulsion composition, the compositions are easily prepared simply by combining all the ingredients in a suitable vessel or container. The order of mixing the ingredients is not particularly important and generally the various ingredients can be added sequentially or all at once or in the form of aqueous solutions of each or all of the primary detergents and cosurfactants can be separately prepared and combined with each other and with the perfume. The magnesium salt, or other multivalent metal compound, when present, can be added as an aqueous solution thereof or can be added directly. It is not necessary to use elevated temperatures in the formation step and room temperature is sufficient.
The instant all purpose cleaning microemulsion compositions explicitly exclude alkali metal silicates and alkali metal builders such as alkali metal polyphosphates, alkali metal carbonates, alkali metal phosphonates and alkali metal citrates because these materials, if used in the instant composition, would cause the composition to have a high pH as well as leaving residue on the surface being cleaned.